The invention relates to the support for a metallurgical vessel, particularly a tiltable and/or revolving steel mill converter which is held in one or several annular supports or raceways, or if necessary, several such supports which surround the vessel but are spaced a distance from it, by means of individual or joined support claws attached to the vessel wall, and pliable, extendible and/or compressible tie rods positioned parallel and/or at right angles to the longitudinal axis of the vessel. The tie rods are under initial stress, so that initial stress units are formed consisting each of a claw with clamp heads, extendible tie rods, and an annular support and/or raceway with clamp heads.
Bearings of a metallurgical vessel require additional means to accommodate thermal balance relative to the apparatus supporting and surrounding the vessel. The usual and proven practical vessel bearings afford a special status to those using in the system initial stress tie rods. The vessels suspended from pliable, expandible tie rods in the annular support may be tilted into any desired tilting position without jolts, and nontiltable vessels may be placed without difficulties relative to the great thermal expansion forces involved with optimum utilization of the tie rods stressed by tensile forces.
For each of the most important stress or load directions occurring in operation, tie rods are provided and arranged in the stress direction. At right angle with these stress directions the tie rods, therefore, do not receive any essential forces. They bend in these directions, and thus make the bearing flexible or yielding when thermal stress occurs. Another advantage of the initial stress system results from the elasticity of the tie rods in the area of the so-called Hooke stress where, as is well known, the extension of the tie rod increases linearly with the load.
The system of the initial stress, pliable, expandible tie rods operates in such a manner that the tie rods are stressed during assembly of the vessel up to an initial stress force. Thus, the tie rods lengthen by the intended amount, while the parts joined by the tie rods (claw and annular support and/or claw and raceway) are simultaneously compressed by a certain amount. If an operating force is then added consisting of the converter weight together with the weight of its brick lining and its contents, the tie rods are stressed even more, and the claws and/or annular supports or raceways are relieved. When altering the operating force from zero to a maximum force, the force in the tie rods only changes by the differential force which is the maximum force minus the initial stress force, if the connection of the claw with the annular support and/or claw with the raceway is under initial stress with the operating force. If, however, the initial stress force is lacking, this differential force increases considerably, and matches the maximum force.
The longer such tie rods are selected, the easier a slightly S-shaped bending of the tie rods occurs, thus providing a corresponding pliability vs. thermal stress. For a greater constructive length of the tie rods, therefore, spacing pipes are inserted between the claw and the annular support and/or between the claw and the raceway, their length thus representing a means for influencing the bending characteristics of the tie rods.
German DE-PS No. 15 33 909 discloses how such bearings for vessels are provided as a connection between a metallurgical vessel and an annular support or raceway according to the initially mentioned combination by means of a desired number of initial stress units. Depending on the great stress on a tie rod resulting from the weight of the vessel together with its brick lining and the weight of its contents, it is necessary to provide more than one tie rod in a mounting area between the vessel and the annular support and/or between the vessel and the raceway. It is known to arrange two such tie rods in a mounting area side by side or superimposed. The size of the individual tie rod cross sections is, however, limited by the initial stress to be applied and by the surface compression occurring between claw and annular support and/or raceway.
Larger vessels, on the other hand, require tie rods of accordingly larger dimensions, which may be burdened with greater loads, accordingly. However, the stress or load capacity of individual tie rods is limited by their coordinated initial stress force. Practice has shown that such initial stress forces can only be managed somewhat easily up to the range of about 300 Mp utilizing the available mobile hydraulic jigs or clamping devices, so that the capacity of tie rods made of high-duty materials cannot be exploited fully. On the other hand, the arrangement of any desired number of tie rods, each forming an initial stress unit, on annular supports or raceways is impossible, as the latter must be kept narrow, if only in view of their economical manufacture. Such annular supports or raceways may also be kept narrow which is a result of their bending stress. These dimensioning endeavors would be opposed by inappropriate demands on the part of the required base areas for the connection of the tie rods, because corresponding cross sectional areas would have to be created in order to accommodate the desired number of tie rods.
It is the object of the present invention to better utilize the stress capacity of the initially mentioned initial stress units, in order to make do with the area for attachment available on the annular support and/or raceway ends for a relatively small number of initial stress units.
The invention here solves this problem for the initially described vessel attachments provided with the above mentioned initial stress units by superimposing at least one additional initial stress unit whose clamp heads are each supported indirectly or directly on the first initial stress stage, so that each initial stress unit penetrates the other and/or others with its expandible tie rods. This solution has several advantages. A double or multiple initial stress unit results, onto which the necessary initial stress forces and/or loads of at least two initial stress units are transferred as usual. The distribution of the load is onto two separate initial stress units, to be true, but in such a way that one initial stress unit receives the other within itself. This results in a substantial space-saving arrangement leading to considerable additional advantages in the remaining design of the vessel construction.
Another advantage is that the application of the initial stress force and its release may take place in one or more stages in such a way that at first one initial stress unit is treated with the maximum force of the available hydraulic jig, and then each further initial stress unit. This makes it possible to fully utilize, double and/or multiply the available maximum forces of the currently marketed hydraulic jig, or to keep the hydraulic jigs used relatively small. In view of the construction, the initial stress unit, according to the invention, has especially favorable results, with narrow annular supports in their pivot pin area that often during reconstruction and related vessel enlargements cause difficulties. The high space-saving feature of the structure permits arrangement of the tie rods transmitting great initial stress forces on especially narrow annular supports.
According to a further improvement elaborating on the concept of the invention, several of the superimposed initial stress units are arranged symmetrically with a common central axis. This serves to simplify the systematic computation of equally large initial stress forces in the individual expandible tie rods. This space-saving arrangement is further improved on by arranging several clamp heads of different initial stress units concentrically with the common center axis.
The application of the initial stress forces by means of the above-mentioned hydraulic jigs is simplified if the tie rods of one initial stress unit are arranged on an interior ground plan surface, and the tie rods of the other initial stress units on exterior annular ground plan surfaces. The application of the initial stress forces in stages is, furthermore, facilitated by the fact that the clamp heads of several initial stress units are supported on each other. The clamp heads may be mounted to support themselves independently by their clamping nuts on the claws and annular supports and/or raceways to be rigged, which contributes to an easy independent initial stress transmittal.